A couple enjoys a sunny day under a cherry tree, May 1, 2012, at Petrin Hill, in Prague. (Michal Cizek/AFP/Getty Images)

A woman takes a photograph of tulips during the Tanto Tulip Festival, May 1, 2012 in Toyooka, Japan. (Buddhika Weerasinghe/Getty Images)

A model showcases designs by Johanna Johnston on the catwalk on day two of Mercedes-Benz Fashion Week Australia Spring/Summer 2012/13 at Overseas Passenger Terminal, May 1, 2012 in Sydney, Australia. (Ryan Pierse/Getty Images)

Paulina Hernandez, center, screams beside her sisters Daniela Hernandez, left, and Jimena Hernandez, at a playground set up to celebrate Children's Day in downtown Mexico City, April 30, 2012. (Alexandre Meneghini/AP Photo)